I don't think this trick will be useful anyways, because it is a bug abuse and since you published it in the official forum Devs will fix this 
It's not abooze. When you have "use faction banner" selected, you can't really pick which side (red/blue etc..) you're going to start on unless maybe you loaded up the map quickly and are one of the first few people to select a side. Then you might still get rebalanced on the second round. Also, as Blondin mentioned, you could be stuck on the side that loses for the entire map.
On the first round, the balance divides the teams fairly evenly and then start throwing people back and forth on the 2nd round. I'm assuming the use faction banner option keeps me on the same side for the entire map because the small clusters of people with the same clan banner and higher k/d ratios are going to be the first people to get rebalanced. If everyone had "use faction banner" selected, then it wouldn't matter because the balance would probably happen with team numbers and global k/d ratios. To be honest, I really don't know much about the specifics of how balance works, I've just overheard people complaining about getting team switched a lot so I'm just sharing what has worked for me based on experience.
It might just work for some people and not others.
